1. Field of the Invention
The present invention relates to an auxiliary power unit starting apparatus for a wheelchair, more particularly to a starting apparatus that can start the motor to produce an auxiliary driving power at the time the user is rotating the hand wheel of the wheelchair.
2. Description of the Prior Art
For a disabled people, conventional wheelchair is more than a means of transportation, it is an optimum rehabilitation tool, because the user has to rotate the wheels by hand, and this can exercise the user's hand and is good for rehabilitation. It is to be noted that running on a flat and smooth road is not a difficult thing for the user. However, the user will probably feel hard if running up a slope, and if the slope angle is greater than 15 degrees, the user can't overcome it independently.
Therefore, a power-assisted wheelchair, such as the device of U.S. Pat. Nos. 6,230,831, 5,818,189, 6,354,390 and 5,878,829, has been made to overcome this problem, wherein an electric motor is disposed in the wheel hubs, and the motor starting device is designed in such a way that the electric motor will be started when the user rotate the hand wheel.
To prevent the motor from being started when the user just touches the hand wheel, the hand wheel is generally designed to have a travel distance, that is, only when the hand wheel rotates a certain distance, the electric motor will then be started. Therefore, the travel distance can't be overly long, otherwise, the response of the electric motor will be too slow.
According to the conventional technology, the start of a power assisted wheelchair is generally controlled by precision-control electronic component or sensor. However, using such electronic precision electronic elements will not only increase the cost but also will increase the failure rate.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.